DETERMINATION OF COBALT, COPPER, IRON, NICKEL AND ZINC IN CEMENTED TUNGSTEN CARBIDES WITH COBALT AS A BINDER BY FAAS - MATRIX EFFECT CONTROL BY MULTIVARIATE TECHNIQUE

A new approach for the determination of cobalt, copper, iron, nickel a nd zinc in cemented tungsten carbides with cobalt as a binder by flame atomic absorption spectrophotometry (FAAS) is reported. Real samples were dissolved in phosphoric, hydrochloric and nitric acid. PTFE bomb or alternatively small amounts of HF were used for the enhancement of the recovery of the elements investigated. Synthetic samples were used for interference studies. Multiple linear regression was applied for the control of matrix effects and it proved to be very effective in th e search for interfering elements. Using simple acid based standards, all investigated elements could be determined sequentially in a comple x matrix by using an appropriate method of calculation. The method des cribed has been succesfully applied to real type commercial samples. R esults were compared with those obtained by inductively coupled plasma atomic emission spectrometry (ICP-AES) and X-ray fluorescence spectro metry (XRF), being in good agreement with each other and having relati ve standard deviations better than 5%.